For the safe LPG fracturing of oil and gas wells, as for example proposed by the inventor Dwight Loree in his Patent Cooperation Treaty application no. PCT/CA2007/000342 published Sep. 7, 2007 and related applications, large volumes of nitrogen or other inert gas such as argon are required for delivery to fracturing equipment such as blenders and bulkers used at the well site. A design previously used by GasFrac Energy Services Inc. used high pressure pumps of the centrifugal type, pumping high pressure (10 k psi), low volume (50 cm3/min), which proved inadequate for intended use in the blenders and bulkers and needed to be supplemented by N2 tube trailers. Additional equipment requiring manual operation caused more people to be within the hazard area at the well site. The inventor investigated commercial equipment suitable for the purpose and found nothing available, and therefore invented what is disclosed in this document.